1. Technical Field
The present invention relates to an apparatus for driving a gyro sensor and a control method thereof.
2. Description of the Related Art
Recently, mobile devices equipped with a gyro sensor (an accelerometer, an angular velocity (gyro) sensor, or a terrestrial magnetism sensor, and the like) using inertial input applied from the outside have been launched. Among the various gyro sensors, a gyro sensor measures an angular velocity by detecting an amount of applied rotatory power of an object. An angular velocity may be obtained by Coriolis' force “F=2 mΩV” wherein m is mass of a sensor Mass, Ω is an angular velocity desired to be measured, and V is a motion velocity of the sensor Mass.
Gyro sensors are commonly used for attitude control in aircraft, rockets, robots, and the like, and for image stabilization (or hand-shaking correction) in cameras, binoculars, and the like. Recently, gyro sensors have been installed in smart phones, and in order to smoothly perform the foregoing function, gyro sensors are required to have a high signal-to-noise ratio (SNR).
Thus, in order to increase an SNR of a gyro sensor, an output signal from a gyro sensor should be large and noise related to a control circuit of the gyro sensor controlling the output signal should be small. Conventionally, as described in the related art document below, a gyro sensor cannot secure a high SNR due to noise generated as a quadrature signal (i.e., a signal due to mismatch of components generated during the process of manufacturing a gyro sensor) and jitter (phase noise) of a synchronous detection clock in connection with the control circuit are mixed.
Also, ideally, a considerable portion of the quadrature signal may be removed through a synchronous detection circuit (or a demodulator), but noise is generated by the quadrature signal due to a change in PVT of the control circuit or a degradation of the gyro sensor.